1. Field of the Invention
The present invention relates to an industrial X-ray photosensitive material and, particularly, relates to an industrial X-ray photosensitive material having high sensitivity and high contrast.
2. Description of the Related Art
Industrial X-ray photosensitive materials are used for irradiating a subject with X-rays, and detecting an intensity of transmitted X-rays, in order to inspect an interior or detect a defect on a surface of an industrial member. In this field, in addition to X-rays, γ-rays from a radioactive isotope, or high energy rays or particle rays from a particle accelerator are used as a radiation ray source for recording. In addition, in recording with a photosensitive material, lamination of a thin metal foil such as a lead foil and the photosensitive material and irradiation of the radiation rays is frequently conducted. In this case, the metal foil subjected to irradiation with the radiation rays and a coated silver halide particle itself absorb the irradiation energy, and release a secondary electron beam or the like, which is finally used to expose the photosensitive material. Therefore, all of these are image recording by irradiation with radiation rays other than light. A latent image formed by irradiation with radiation is developed with a developer to form a blackened silver image. The industrial X-ray photosensitive materials are designed to detect small defects of an industrial member, and an extremely high contrast is required in order to detect the small defects. In order to attain high contrast, it has been a conventional means in industrial X-ray photosensitive materials to increase an amount of coated silver, and soften coated layers in film design. For this reason, an industrial X-ray photosensitive material product having a large amount of coated silver has problems in that a cost is determined by the cost of silver, and in that, because of having a large amount of coated silver and softened layers, a processing time becomes long, which results in a low efficiency in a detection operation and the like. Therefore, according to the conventional technology, it has been difficult to reduce the amount of coated silver, realize both high sensitivity and high contrast, and further provide rapid processing suitability.
The use of a tabular silver halide particle is known as a means for enhancing a sensitivity of silver halide. For example, Japanese Patent Application Laid Open (JP-A) No. 9-106018 discloses that an industrial X-ray photosensitive material using a tabular silver halide particle having an average aspect ratio of 2 or more with respect to 50% or more of a total particle projection area has a higher photographic sensitivity to radiation rays as compared with a photographic sensitivity to radiation rays obtained by using a non-tabular silver halide particle having the same particle volume, and gives high sensitivity without increasing an amount of silver.